Defecation 2: Internal anorectal resistance is a critical factor in defecatory disorders

Background

The aim of this study was to test our hypothesis that the reason why imaging is of little assistance in diagnosing “constipation” causes may be related to the high sensitivity of internal anorectal flow resistance in defecation to small changes in geometry. We applied a mathematical model to describe the effects on flow mechanics of observed changes in the shape of the rectum and anus during defecation.

Methods

Three groups of patients were studied with video proctograms. Group 1 comprised 4 patients with normal defecation studied with video proctography or magnetic resonance imaging (MRI). Group 2 comprised 8 patients with fecal incontinence, studied by video X-ray electromyography. Group 3 comprised 8 patients with constipation evaluated by video MRI.

Results

Three muscle vectors open the anorectal angle prior to defecation, causing the anorectal luminal diameter to increase to approximately twice its resting size. These vectors are forwards (anterior wall), backwards and downwards (posterior wall). Resistance to passage of a fecal bolus through the anorectum is determined by viscous friction against the anorectal wall and by the energy required to deform the bolus as it flows. The observed changes in anorectal geometry serve to reduce both the viscous friction in the anus and the deformation of the bolus, which reduces the force required to facilitate its passage through the anus. For example, if the effective diameter of the anus is doubled during defecation, the frictional resistance is reduced by a factor of 8.

Conclusions

The sensitivity of flow resistance to geometry explains why MRI or computed tomography (CT) scans taken during defecation are not often helpful in diagnosing causation. Small changes in geometry can have a disproportionate affect on flow resistance. Combining accurate directional measurements during dynamic MRI or CT scans taken during defecation with observations of bolus deformation, and if possible, simultaneous anorectal manometry, may provide clinically helpful insights on patients with anorectal evacuation disorders.     

The puborectal continence reflex: a new regulatory mechanism controlling fecal continence

Purpose

Fecal continence is maintained by voluntary and involuntary contraction of the anal sphincter, and voluntary contractions of puborectal muscle. We investigated whether the puborectal muscle can control fecal continence not only by voluntary contractions but also by involuntary contractions.

Methods

We performed anorectal function tests in 23 healthy subjects. The anorectal pressure test was used to investigate voluntary contractions of the puborectal muscle. The balloon retention test was used to assess if the puborectal muscle can contract involuntarily.

Results

During the balloon retention test, we observed an involuntary contraction of the puborectal muscle, which gradually increased during progressive filling of the rectum. The maximal involuntary contraction of the puborectal muscle was significantly stronger and longer than its maximal voluntary contraction (150 versus 70 mmHg, P?<?0.001 and 5.8 versus 1.5 min, P?<?0.001).

Conclusions

We found that the puborectal muscle is able to contract involuntarily during rectal dilatation. It is a new regulatory mechanism, called the puborectal continence reflex, which controls fecal continence by involuntary contraction of the puborectal muscle. It seems to be initiated by dilatation at the level of the puborectal muscle. Presumably, the puborectal continence reflex protects many patients with anal sphincter dysfunctions from fecal incontinence.

     

MR-defecography in obstructed defecation syndrome (ODS): technique, diagnostic criteria and grading

Background

The aim of this study was to evaluate the use of a magnetic resonance (MR)-based classification system of obstructive defecation syndrome (ODS) to guide physicians in patient management.

Methods

The medical records and imaging series of 105 consecutive patients (90 female, 15 male, aged 21–78 years, mean age 46.1 ± 5.1 years) referred to our center between April 2011 and January 2012 for symptoms of ODS were retrospectively examined. After history taking and a complete clinical examination, patients underwent MR imaging according to a standard protocol using a 0.35 T permanent field, horizontally oriented open-configuration magnet. Static and dynamic MR-defecography was performed using recognized parameters and well-established diagnostic criteria.

Results

Sixty-seven out of 105 (64 %) patients found the prone position more comfortable for the evacuation of rectal contrast while 10/105 (9.5 %) were unable to empty their rectum despite repeated attempts. Increased hiatus size, anterior rectocele and focal or extensive defects of the levator ani muscle were the most frequent abnormalities (67.6, 60.0 and 51.4 %, respectively). An MR-based classification was developed based on the combinations of abnormalities found: Grade 1 = functional abnormality, including paradoxical contraction of the puborectalis muscle, without anatomical defect affecting the musculo-fascial structures; Grade 2 = functional defect associated with a minor anatomical defect such as rectocele ≤2 cm in size and/or first-degree intussusception; Grade 3 = severe defects confined to the posterior anatomical compartment, including >2 cm rectocele, second- or higher-degree intussusception, full-thickness external rectal prolapse, poor mesorectal posterior fixation, rectal descent >5 cm, levator ani muscle rupture, ballooning of the levator hiatus and focal detachment of the endopelvic fascia; Grade 4 = combined defects of two or three pelvic floor compartments, including cystocele, hysterocele, enlarged urogenital hiatus, fascial tears enterocele or peritoneocele; Grade 5 = changes after failed surgical repair abscess/sinus tracts, rectal pockets, anastomotic strictures, small uncompliant rectum, kinking and/or lateral shift of supra-anastomotic portion and pudendal nerve entrapment.

Conclusions

According to our classification, Grades 1 and 2 may be amenable to conservative therapy; Grade 3 may require surgical intervention by a coloproctologist; Grade 4 would need a combined urogynecological and coloproctological approach; and Grade 5 may require an even more complex multidisciplinary approach. Validation studies are needed to assess whether this MR-based classification system leads to a better management of patients with ODS.     

The influence of age on posterior pelvic floor dysfunction in women with obstructed defecation syndrome

Background

Knowledge of risk factors is particularly useful to prevent or manage pelvic floor dysfunction but although a number of such factors have been proposed, results remain inconsistent. The purpose of this study was to evaluate the impact of aging on the incidence of posterior pelvic floor disorders in women with obstructed defecation syndrome evaluated using echodefecography.

Methods

A total of 334 patients with obstructed defecation were evaluated using echodefecography in order to quantify posterior pelvic floor dysfunction (rectocele, intussusception, mucosal prolapse, paradoxical contraction or non-relaxation of the puborectalis muscle, and grade III enterocele/sigmoidocele). Patients were grouped according to the age (Group I?=?patients up to 50?years of age; Group II?=?patients over 50?years of age) to evaluate the isolated and associated incidence of dysfunctions. To evaluate the relationship between dysfunction and age-related changes, patients were also stratified into decades.

Results

Group I included 196 patients and Group II included 138. The incidence of significant rectocele, intussusception, rectocele associated with intussusception, rectocele associated with mucosal prolapse and 3 associated disorders was higher in Group II, whereas anismus was more prevalent in Group I. The incidence of significant rectocele, intussusception, mucosal prolapse and grade III enterocele/sigmoidocele was found to increase with age. Conversely, anismus decreased with age.

Conclusions

Aging was shown to influence the incidence of posterior pelvic floor disorders (rectocele, intussusception, mucosa prolapse and enterocele/sigmoidocele), but not the incidence of anismus, in women with obstructed defecation syndrome.     

Selection criteria for anterior rectal wall repair in symptomatic rectocele and anterior rectal wall prolapse

PURPOSE: This study was undertaken to determine the outcome and changes produced by an endorectal anterior wall repair in objective functional parameters using anorectal manometry and defecography and to asses their usefulness in the selection of patients for the operation. METHODS: Between 1986 and 1990, we performed a prospective study of 76 consecutive patients with symptomatic rectocele and/or an anterior rectal wall prolapse. All patients were studied prospectively according to a fixed protocol. Standard questionnaire, defecation diary, clinical examination, defecography, and anal manometry were performed preoperatively and three to four months postoperatively. RESULTS: Three months postoperatively, 38 patients (50 percent) had no complaints at all (excellent result), 32 (42 percent) had only a minor complaint (good result), and in 6 patients (8 percent) the complaints were essentially unchanged (unsatisfactory result). After one year, similar figures were obtained. The postoperative mean stool frequency in all patients after three months was significantly increased (P <0.05) but not after one year. Postoperative defecographies showed a complete absence or significant diminution of the rectocele at three months and were significantly correlated with relief of symptoms. An inverse correlation was found between improvement in incontinence grade after operation and (larger) preoperative volume at which urge to defecate was elicited, making it a good predictor of improvement in incontinence by the operation. CONCLUSIONS: The anterior rectal wall repair positively influences rectal sensation in patients with incontinence and/or obstructed defecation caused by a rectocele and/or an anterior rectal wall prolapse. Anorectal manometry was useful in studying the beneficial physiologic effects of the endorectal repair. In patients with no previous pelvic surgery, a large urge to defecate volume is a good predictor of a good clinical outcome.     

Management of synchronous rectal and prostate cancer

Purpose

Although well described, there is limited published data related to management on the coexistence of prostate and rectal cancer. The aim of this study was to describe a single institution’s experience with this and propose a treatment algorithm based on the best available evidence.

Methods

From 2000 to 2011, a retrospective review of institutional databases was performed to identify patients with synchronous prostate and rectal cancers where the rectal cancer lay in the lower two thirds of the rectum. Operative and non-operative outcomes were analysed and a management algorithm is proposed.

Results

Twelve patients with prostate and rectal cancer were identified. Three were metachronous diagnoses (>3-month time interval) and nine were synchronous diagnoses. In the synchronous group, four had metastatic disease at presentation and were treated symptomatically, while five were treated with curative intent. Treatment included pelvic radiotherapy (74?Gy) followed by pelvic exenteration (three) and watchful waiting for rectal cancer (one). The remaining patient had a prostatectomy, long-course chemoradiotherapy and anterior resection. There were no operative mortalities and acceptable morbidity. Three remain alive with two patients disease-free.

Conclusions

Synchronous detection of prostate cancer and cancer of the lower two thirds of the rectum is uncommon, but likely to increase with rigorous preoperative staging of rectal cancer and increased awareness of the potential for synchronous disease. Treatment must be individualized based on the stage of the individual cancers taking into account the options for both cancers including EBRT (both), surgery (both), hormonal therapy (prostate), surgery (both) and watchful waiting (both).     

Laparoscopic-assisted low anterior resection of the rectum��a review of the fascial composition in the pelvic space

Introduction

Outcomes of rectal cancer treatment depend on the operative technique, and complication rates vary. Complications can occur during mobilization of the rectum, with damage to the ureter, autonomic nerves, and the rectum itself. Frequencies of these complications can be reduced by careful dissection of the correct tissue plane in the pelvic space.

Methodology

This paper reviews the fascial composition of the rectum for low anterior resection of the rectum. To date, fascial composition of the pelvic space has been considered based on clinical anatomy and histological examination of cadaveric specimens. However, clarification of fascial composition is clearly limited, to a certain extent, in histological examinations compared with clinical anatomy.

Conclusions

First, some degree of dissociation must exist between the histological examination and clinical anatomy. Second, surgeons should not consider fascia encountered intraoperatively as an artifact. To address these difficult issues, consideration should be made purely from the perspective of clinical anatomy. Originally, the trunk was embryologically regarded as a multi-layered structure (like an onion). Understanding the fascial composition of the abdomen is comparatively easy when approached from this perspective. If this theory is adapted to the pelvic space in order to avoid antilogy, an understanding of the fascial composition of the pelvic space should also be possible. We review previous papers based on this theory.     

Dyssynergic Defecation: A Treatable Cause of Persistent Symptoms When Inflammatory Bowel Disease Is in Remission

Background

Introduction of biologic agents in inflammatory bowel disease (IBD) has increased the likelihood of disease remission. Despite resolution of active inflammation, a subset of IBD patients report persistent defecatory symptoms.

Aim

To evaluate a group of patients with inflammatory bowel disease with suspected functional defecatory disorders, by use of anorectal manometric testing and subsequent biofeedback therapy.

Methods

A group of IBD patients with persistent defecatory problems despite clinical improvement were included in this study. These patients had no evidence of left-sided disease. Endoscopic and radiographic study findings and timing in relation to the manometry study were recorded. Anorectal manometry was performed by the standard protocol and included rectal sensory assessment, ability to expel a balloon, and pressure dynamics with simulated defecation.

Results

Thirty IBD patients (Crohn’s 23 patients; ulcerative colitis six patients) presented with defecatory disorders including constipation (67 %) increased stooling (10 %), and rectal urgency and/or incontinence and rectal pain (6 %). All but one patient had anorectal manometric criteria of dyssynergia (presence of anismus motor pattern and inability to expel the balloon). Of the patients who completed biofeedback therapy, 30 % had a clinically significant (≥7-point) improvement in SIBDQ score, with a reduction in health-care utilization after a six-month period (p = 0.02).

Conclusions

Despite remission, some inflammatory bowel disease patients have persistent defecatory symptoms. Defecatory symptoms may not be predictive of an underlying inflammatory disorder. Lack of inflammatory activity and absence of left-sided disease should prompt investigation of functional disorders. Anorectal manometric testing and biofeedback therapy for patients with a diagnosis of dyssynergia may be a useful therapy.     

Symptomatische Rektozele mit Outlet-Obstruction?II

Background

Due to prolapse of the anterior wall of the rectum and the resultant trapping of stool, most patients with outlet obstruction (mostly women) have the sensation of incomplete rectal emptying. Instrument-based examinations can confirm the presence of a rectocele but do not provide objective surgical diagnoses. Our diagnostic procedures revealed preoperatively reduced sphincter pressure at rest.

Materials and Methods

In our study, n=171 female patients with symptomatic rectocele underwent stapled transanal resection during the period from 01.01.2001 to 30.06.2006. A circular mucosal ring was resected along with the rectocele as a full-wall excision according to the authors?? modification using only one stapler.

Results

No complications were observed immediately post surgery, n=139 female patients responded to the questionnaire sent to them in the context of postoperative evaluation. This is equivalent to a feedback quota of 81.3%, of which 119 patients participated in the statistic evaluation since some questionnaires were not completed. Improvement in rectal emptying resulting from the procedure was based on subjective estimation alone.

Conclusions

Against the background of a lack of objective criteria to date for surgical diagnoses in symptomatic rectocele, stapled transanal resection was assessed to be a technically simple and effective therapy.     

Physiology of rectal sensations

PURPOSE: The first awareness of balloon inflation (first sensation (FS)), flatus sensation (constant sensation (CS)), urge to defecate (UD), and maximum tolerated threshold (MTT) are the four commonly evaluated rectal sensations. The traditional view that these sensations are attributable to pelvic floor mechanoreceptor stimulation is challenged by current evidence in favor of rectal wall mechanoreceptors. The aim of this study was to determine the physiology of these sensations, using a dynamic mathematic model of the rectum. METHODS: In a group of 15 healthy adult volunteers (11 female and 4 male; median age, 51.5 (range, 31–74) years), the polynomial behavior of the two smooth muscle components of a dynamic mathematic model of the rectum was analyzed to find strain levels of smooth muscle activity in relation to corresponding strain levels of each of the four “rectal” sensations. RESULTS: Longitudinal and circular smooth muscle relaxation appeared to be the rate detection and signaling mechanisms, respectively. The latter triggered sensations of CS, UD, and MTT. FS was an anal canal sensation, related temporally with onset of rectoanal inhibitory reflex.In vitro validation of the model suggested MTT to be a physiologic protective mechanism associated probably with tetanic smooth muscle contraction. CONCLUSIONS: Evaluation of rectal sensations should be confined to CS and UD because MTT is painful and does not contribute any additional information, and FS is not a true rectal phenomenon.     

Use of the gluteus maximus muscle as the neosphincter for restoration of anal function after abdominoperineal resection

Background

Our aim was to evaluate complications and long-term functional outcome in patients who had sphincter reconstruction using the gluteus maximus muscle as the neosphincter after abdominoperineal resection for rectal cancer treatment.

Methods

Seven patients underwent reconstruction from 2000 to 2010. First, the sigmoid colon was brought down to the perineum as a perineal colostomy, with the procedure protected by a loop ileostomy. Reconstruction of the sphincter mechanism using the gluteus maximus took place 3 months later, and after another 8–12 weeks, the loop ileostomy was closed. We studied the functional outcome of these interventions with follow-up interviews of patients and objectively assessed anorectal function using manometry and the Cleveland Clinic Florida (Jorge-Wexner) fecal incontinence score.

Results

The mean follow-up was 56 months (median 47; range 10–123 months). One patient had a perianal wound infection and another had fibrotic stricture in the colocutaneous anastomosis that required several digital dilatations. Anorectal manometry at 3-month follow-up showed resting pressures from 10 to 18 mm Hg and voluntary contraction pressures from 68 to 187 mm Hg. Four patients had excellent sphincter function (Jorge-Wexner scores ≤5).

Conclusions

Our preliminary results show that sphincter reconstruction by means of gluteus maximus transposition can be effective in restoring gastrointestinal continuity and recovering fecal continence in patients who have undergone APR with permanent colostomy for rectal cancer. Furthermore, the reconstruction procedure can be performed 2–4 years after the APR.     

Critical reappraisal of anorectal function tests in patients with faecal incontinence who have failed conservative treatment

Objective

Anorectal function tests are often performed in patients with faecal incontinence who have failed conservative treatment. This study was aimed to establish the additive value of performing anorectal function tests in these patients in selecting them for surgery.

Patients and methods

Between 2003 and 2009, all referred patients with faecal incontinence were assessed by a questionnaire, anorectal manometry and anal endosonography. Patients with diarrhea, inflammatory bowel disease, pouches or rectal carcinoma were excluded.

Results

In total, 218 patients were evaluated. Of these, 107 (49%) patients had no sphincter defects, 71 (33%) had small defects and 40 (18%) had large defects. Anorectal manometry could not differentiate between patients with and without sphincter defects. Patients with sphincter defects were only found to have a significantly shorter sphincter length and reduced rectal capacity compared to patients without sphincter defects. Forty-three patients (20%) had a normal anal pressures ≥40?mmHg. Seventeen patients (8%) had also a dyssynergic pelvic floor both on clinical examination and anorectal manometry. Fifteen patients (7%) had a reduced rectal capacity between 65 and 100?ml. There was no difference in anal pressures or the presence of sphincter defects in these patients compared to patients with a rectal capacity >150?ml. There was no correlation between anorectal manometry, endosonography and faecal incontinence severity scores.

Conclusion

In patients with faecal incontinence who have failed conservative treatment, only anal endosonography can reveal sphincter defects. Anorectal manometry should be reserved for patients eligible for surgery to exclude those with suspected dyssynergic floor or reduced rectal capacity.     

Characterization of special propulsive contractions during rectal evacuation in a canine model of intestinal extrinsic denervation and rectal transection

Purpose

The mechanism for the initiation of giant migrating contractions (GMCs) associated with defecation is not well known. The aim of this study was to describe the characteristics of special propulsive contractions (SPCs), such as GMCs, during evacuation in four experimental dog models, with emphasis on denervation.

Materials and methods

Twenty healthy dogs were used in this study, and they were divided into four groups, i.e., control (underwent force transducer implantation alone), denervation (underwent transection of the descending nerve fibers along the caudal mesenteric artery (CMA)), transection (underwent transection of the rectum, which corresponds to transection of the enteric nerve fibers), and denervation-plus-transection (underwent transection of the descending nerve fibers along the CMA and transection of the rectum). Colonic contractile activities were continuously recorded on a computer. Five force transducers were implanted at the serosal surfaces of the colon (C1-R). The consistency of dog feces was checked daily. The parameters of rectal relaxation (RR), defecation characteristics, and SPCs, such as motility index (MI), duration, and frequency, were measured.

Results

In the control and denervation groups, GMCs were observed with evacuation, and RR occurred synchronously with the initiation of GMCs. On the other hand, in the transection and denervation-plus-transection groups, strong force contractions without RR occurred only during evacuation. The MI and duration of the transection and denervation-plus-transection groups were higher than those of other groups (p?<?0.05). The frequency of SPCs was the highest in the denervation-plus-transection group.

Conclusions

In conclusion, the continuity of enteric nerves is necessary for the occurrence of GMCs and rectal relaxation (RR).     

Clinical predictors and gender-wise variations in dyssynergic defecation disorders

Background

There is insufficient data from India regarding clinical predictors of dyssynergic defecation.

Aim

To identify demography, symptom, and colonoscopic parameters that can predict dyssynergic defecation (DD) among patients with chronic constipation (CC) and to compare the profile among male and female patients with DD.

Methods

Data collected from three centers during June 2014 to May 2017 included age, gender, symptom duration, form and consistency of stools, digital examination, colonoscopy, and anorectal manometry (ARM). Patients were grouped based on ARM diagnosis: group I (normal study) and group II (DD). The two groups were compared for demography, symptom profile, and colonoscopy findings. Gender-wise subset analysis was done for those with the normal and abnormal ARM using chi-square and unpaired t tests.

Results

Of 236 patients with CC evaluated, 130 (55%) had normal ARM and 106 (45%) had DD. Male sex, straining during defecation, bleeding per rectum, and abnormal colonoscopic diagnosis were significantly more common in group II. While bleeding per rectum and absence of urge to defecate were more common in males (p?<?0.02), straining, digital evacuation, and hard stools were commoner in females with DD.

Conclusion

Straining during defecation, bleeding per rectum, and abnormal colonoscopy findings were more common in patients with DD. Symptoms of bleeding per rectum and absence of urge to defecate in men and straining during defecation in female patients were significantly associated with DD. Symptoms differ in males and females with DD.

     

Evaluation of two-dimensional intraoperative neuromonitoring for predicting urinary and anorectal function after rectal cancer surgery

Purpose

The aim of this study was to compare the results of two-dimensional intraoperative neuromonitoring (IONM) with the postoperative urinary and anorectal function of rectal cancer patients.

Methods

A consecutive series of 35 patients undergoing low anterior resection were investigated prospectively. IONM was performed with electric stimulations of the pelvic splanchnic nerves under simultaneous manometry of the bladder and electromyography (EMG) of the internal anal sphincter (IAS). Urinary and anorectal function were evaluated preoperatively and at follow-up by standardized questionnaires, digital rectal examination scoring system, and long-term catheterization rate.

Results

The rate of postoperative newly developed bladder dysfunction was 17 %. IONM with bladder manometry had a sensitivity of 100 %, specificity of 96 %, positive predictive value of 83 %, negative predictive value of 100 %, and overall accuracy of 97 %, respectively. The proportion of patients with severely impaired anorectal function at follow-up was 8 %. The sensitivity, specificity, and positive and negative predictive values for IONM with EMG of the IAS were, respectively, 100, 96, 67, and 100 % with an accuracy of 96 %. The degree of agreement for IONM with EMG of the IAS was good for anorectal function (к?=?0.780) and poor for urinary function (к?=?0.119). IONM with bladder manometry yielded a very good degree of agreement for urinary function (к?=?0.891) and a fair agreement for anorectal function (к?=?0.336).

Conclusions

The two-dimensional IONM method is suitable for verification of bladder and IAS innervation. Accurate prediction of urinary and anorectal function necessitates both bladder manometry and EMG of the IAS.     

Rectal prolapse traumatizes rectal neuromuscular microstructure explaining persistent rectal dysfunction

Purpose

Internal rectal prolapse is common and correlates with age. It causes a plug-like physical obstruction and is a major cause of defecation disorder. The progressive distortion of the prolapsing rectum likely causes secondary defects in the rectal wall, which may exacerbate rectal dysfunction. We undertook a prospective observational study to detect and quantify the neurologic and histopathologic changes in the rectal wall.

Methods

We examined dorsal and ventral rectal wall specimens from consecutive patients with internal rectal prolapse undergoing stapled transanal rectal resection (STARR). We subjected specimens to histopathologic and neuropathologic assessment, including immunohistochemistry. We also recorded patients’ clinical and demographic characteristics and sought correlations between these and the pathologic findings.

Results

We examined 100 specimens. The severity of rectal prolapse and the extent of descent of the perineum correlated significantly with age. Concomitant hemorrhoidal prolapse was noted in all male patients and in 79 % of female patients. Muscular and neuronal defects were detected in 94 and 90 % of the specimens, respectively. Only four specimens (4 %) were free of significant structural defects.

Conclusion

Rectal prolapse traumatizes the rectum causing neuromuscular defects. The tissue trauma is due to shearing forces and ischemia caused by the intussusception. This initiates a self-reinforcing vicious circle of physical and functional obstruction, further impairing rectal evacuation and causing constipation and incontinence. The correlation between extent of prolapse and age suggests that internal rectal prolapse can be considered a degenerative disorder. Neural and motor defects in the wall of the rectum caused by rectal prolapse are likely irreversible.

     

Neurovascular antropylorus perineal transposition using inferior rectal nerve anastomosis for total anorectal reconstruction: preliminary report in humans

Background

Technical feasibility of inferior rectal nerve anastomosis to the anterior vagus branch of the perineally transposed antropyloric valve for total anorectal reconstruction has been previously demonstrated in cadavers. To the best of our knowledge, the present study is the first report of using this procedure in humans.

Methods

Eight patients [mean age 35.5 years (range 15–55 years); (male/female = 7:1)] underwent the procedure. The antropyloric valve with its anterior vagus branch was mobilized based on the left gastroepiploic arterial pedicle. The antral end was anastomosed to the distal colon. The anterior vagus nerve was anastomosed by epineural technique to the inferior rectal nerve in the perineum. A diverting proximal colostomy was maintained for 6 months. Anatomical integrity of the graft (on magnetic resonance imaging scans), its arterial pedicle (on computed tomography angiogram) and neural continuity (on ultrasound and pyloric electromyography) were assessed. Functional assessment was performed using barium retention studies, endoscopy, manometry and fecal incontinence scores.

Results

Tension-free end-to-end anastomosis of the anterior vagus nerve to the right (n = 7) and left (n = 1) inferior rectal nerve was achieved. An intact left gastroepiploic pedicle, a healthy graft and neural continuity were visualized on perineal ultrasound. Electromyographic activity was noticed on neural stimulation. Endoscopy and barium studies showed voluntary antral contraction and contrast retention, respectively, in all patients. The mean resting and squeeze pressures were 26.25 mmHg (range 16–62 mmHg) and 50.25 mmHg (range 16–113 mmHg), respectively. St. Mark’s incontinence scores varied between 7 and 12. There were no major surgical complications.

Conclusions

Pudendal (inferior rectal) innervation of the perineally transposed antropylorus in total anorectal reconstruction is feasible and may improve outcomes in selected patients with end-stage fecal incontinence.     

Anorectal gastrointestinal stromal tumors: a retrospective multicenter analysis of 15 cases emphasizing their high local recurrence rate and the need for standardized therapeutic approach

Purpose

This study aims to report our multicenter experience with diagnosis, management, and prognosis of anorectal gastrointestinal stromal tumors (GIST).

Patients and methods

We retrospectively reviewed cases treated and/or followed up at our institutions in the period 2000–2011.

Results

Fifteen patients were identified (eight men and seven women; mean age, 55 years). Presenting symptoms were rectal/perirectal (eight), rectovaginal space (four), or retrovesical/prostatic (three) mass. Primary surgical treatment was local excision (six), deep anterior resection (eight), and palliative diagnostic excision (one). Tumor mean size was 4.8 cm. All but two cases were high risk (Miettinen and Lasota, Semin Diagn Pathol 23:70–83, 2006). R0 resection was achieved in 46 % of cases: one of six local excisions vs. five of seven deep anterior resection (16 vs. 71 %, respectively). All three cases who received total mesorectal excision had R0. Non-R0 status was mainly due to opening of tumor capsule at surgery (Rx). Seven of 14 patients (50 %) developed ≥1 pelvic local recurrences at a mean period of 48.4 months (mean follow-up, 61.6 months). Only two patients developed distant metastasis (adrenal, liver, and peritoneal). Recurrences developed after Rx (three), R1 (two), and unknown R-status (two). Successful mutational analysis in 13 patients revealed KIT mutations in all (10 exon 11, 2 exon 9, and 1 exon 13).

Conclusion

Our results confirm the high local recurrence rate of anorectal GISTs (50 %) which correlates with the common practice of suboptimal oncological primary tumor resection (Rx or R1?=?7/13). This uncommon subset of GISTs needs more standardized oncological surgical approach to minimize the propensity for local disease recurrence.     

Nerve supply to the internal anal sphincter differs from that to the distal rectum: an immunohistochemical study of cadavers

Purpose

Fecal incontinence is a common problem after anal sphincter-preserving operations. The intersphincteric autonomic nerves supplying the internal anal sphincter (IAS) are formed by the union of: (1) nerve fibers from Auerbach’s nerve plexus of the most distal part of the rectum and (2) the inferior rectal branches of the pelvic plexus (IRB-PX) running along the conjoint longitudinal muscle coat. The aim of the present study is to identify the detailed morphology of nerves to the IAS.

Methods

The study comprised histological and immunohistochemical evaluations of paraffin-embedded sections from a large block of anal canal from the preserved 10 cadavers.

Results

The IRB-PX came from the superior aspect of the levator ani and ran into the anal canal on the anterolateral side. These nerves contained both sympathetic and parasympathetic fibers, but the sympathetic content was much higher than in nerves from the distal rectum. All intramural ganglion cells in the distal rectum were neuronal nitric oxide synthase-positive and tyrosine hydroxylase-negative and were restricted to above the squamous-columnar epithelial junction. Parasympathetic nerves formed a lattice-like plexus in the circular smooth muscles of the distal rectum, whereas the IAS contained short, longitudinally running sympathetic and parasympathetic nerves, although sympathetic nerves were dominant.

Conclusions

The major autonomic nerve input to the IAS seemed not to originate from the distal rectum but from the IRB-PX. Injury to the IRB-PX during surgery seemed to result in loss of innervation to the major part of the IAS.     

Anismus: Fact or fiction?

PURPOSE: Although anismus has been considered to be the principal cause of anorectal outlet obstruction, it is doubtful whether contraction of the puborectalis muscle during straining is paradoxical. The present study was conducted to answer this question. METHODS: During the first part of the study, we retrospectively reviewed 121 patients with constipation and/or obstructed defecation (male:female, 10/111; median age, 51 years). All of these patients underwent electromyography (EMG) of the pelvic floor and the balloon expulsion test (BET) in the left lateral position. Evacuation proctography was performed in all of these patients in the sitting position. Both the posterior anorectal angle and the central anorectal angle were measured. EMG and BET were also performed in ten controls (male:female, 4/6; median age, 47). In 147 patients with fecal incontinence (male:female, 24/123; median age, 58) only EMG activity was recorded. Criteria for anismus during straining were increase or insufficient (<20 percent) decrease of EMG activity, failure to expel an air-filled balloon on BET, and decrease or insufficient (<5 percent) increase of anorectal angle on evacuation proctography. Between June 1994 and March 1995, we conducted a second prospective study in a consecutive series of 49 patients with constipation and/or obstructed defecation and 28 patients with fecal incontinence. Both groups were compared with 19 control subjects. In this study, all three tests were performed. EMG and BET were performed both in the left lateral position and in the sitting position. RESULTS: The retrospective study was undertaken by comparing the constipated patients with the incontinent patients and the controls, and the anismus detected by EMG was found in, respectively, 60, 46, and 60 percent. Failure to expel the air-filled balloon was observed in 80 constipated patients (66 percent) and in 9 control subjects (90 percent). Based on posterior anorectal angle and central anorectal angle measurements, anismus was diagnosed in, respectively, 21 and 35 percent of constipated patients. In the prospective study, none of the tests showed significant differences regarding the prevalence of anismus between the two subgroups of patients and the control subjects. The prevalence of anismus only differed between constipated and incontinent patients when the diagnosis was based on BET in the sitting position (67 vs.32 percent;P <0.005). Our study shows that contraction of the puborectalis muscle during straining is not exclusively found in patients with constipation and/or obstructed defecation. The three tests most commonly used for the diagnosis of anismus showed an extremely poor agreement. CONCLUSION: Based on these findings, we doubt the clinical significance of anismus.